starch + glycogen

[sue]

why is it advantageous for starch n glycogen to be large but not soluble?

[Dr.Stein]

As their fate as "storage"

[sue]

ok. thanks. does anyone know wjat proteoglycans are? - and their function.

[victor]

Proteoglycans = polymer combination of glycogen and protein...as far as I know, it's used to build the cell wall of bacteria..

[Dr.Stein]

Proteoglycans and glycoprotein, both are polymers contain glycogen and protein, the difference is which one, glycogen or protein, is more than the other one

[sue]

ok. thanks again. does anyone know how glucose molecules and ions enter a cell passively and actively ?

[Dr.Stein]

Understand this figure

[Dr.Stein]

I have just got this figure, about how insulin effects on glucose transport. I want to share it with you all here If you found it is too complicated for you, please don't sigh, continue to understand or just ignore it. I also try hard to read it

1. Insulin causes receptor autophosphorylation
2. Activated insulin receptor phosphorylates IRS-1
3. Phosphorylated IRS-1 activates PI-3 kinase
4. PI-3 kinase converts PIP2 => PIP3 (activates PDK1)
5. PDK1 activates protein kinase B (PKB)
6. PKB stimulates GLUT-4 translocation



Some events take place on the membrane surface, because the lipid messengers are not soluble in water. Use the back button to return to the main document.

Glossary
IRS-1 = insulin receptor substrate 1
PDK1 = 3-phosphoinositide dependent kinase 1
PI-3K = phosphatidylinositol 3 kinase
PIP2 = phosphatidylinositol 4,5 bisphosphate
PIP3 = phosphatidylinositol 3,4,5 trisphosphate
PKB =protein kinase B

I think the author forgot some arrows...

[sue]

ok. thanks, would anyone know how plants cells protect themselves from their own toxic products

[victor]

they use vacuoles which is bordered by tonoplasts..

[sue]

how do they use their vacuoles? - what happens exactly?

[Dr.Stein]

ok. thanks, would anyone know how plants cells protect themselves from their own toxic products

By lectins. Even plants have an immune system